新农药多噻烷的土壤生态毒性研究

Study on the Soil Ecological Toxicity of Pesticide─Polythiacycloalkane

通过观察土壤呼吸作用强度、需氧细菌总数、真菌总数、硝化作用及固氮酶活性等指标的变化，研究了新农药多噻烷的土壤生态毒性。结果表明，在实验浓度为50～750mg／kg时，土壤呼吸作用强度及异养细菌数均见增加，且与施用浓度呈正相关，可分别达到对照组的1至3倍；真菌总数在750mg／kg时略见抑制，但不出半月又复原；多噻烷对土壤硝化作用呈现抑制效应，50、250、750mg／kg抑制率分别为23.9％、34.7％、51.1％；固氮酶活性在多噻烷浓度较低时(100mg／kg)增高，为对照组的131.81％，但浓度大于300mg／kg后，就表现为抑制作用。

The effect of pesticide polythiacycloalkane on respiration,the quantities of aerobic bacteria and fungi,nitrification and N_2 fixation in an agricultural soil were investigat-ed to study the soil ecological toxicity of pesticide polythiacycloalkane.When the concentra-tions of polythiacycloalkane were used from 50 to 750mg／kg CO_2 production and the aerobic bacteria population were enhanced and the enhancement became higher with the increase of concentrations.Fungi population was reduced at higher concentration(750mg／kg),but the inhibition was temporary and restored after 14 days.Nitrification was inhibited obviously as concentration of polythiacycloalkane increased.Activity of nitrogenase was stimulated to 131.81％ at lower concentration(100mg／kg)of polythiacycloalkane,but depressed when concentration of polythiacycloalkane is higher than 300mg／kg